package PTA.ch03;

import java.util.Scanner;

public class ex02 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int x = sc.nextInt();
        int y = sc.nextInt();
        int r = sc.nextInt();
if(inCircle(x,y,r)){
    System.out.println("yes");
}else{
    System.out.println("no");
}
    }
    public static boolean inCircle(int x, int y, int r){
if(x*x+y*y<r*r){
    return true;
}
return false;

    }
}
